i have LED lighting for my tanks and, they are 2.5 gallons, i only want a few to replace the fake ones i have now. If it isn't a good idea thats fine, but i'm still intrested in knowing what plants would be good if I decide to upgrade my tanks to 5 gallons.

Java fern might be too big for you, I have Java Fern and it's a little bit too big for my 10 gallon, if you choose to go with Java Fern, find a dwarf version of it, or a species that grows very slow.

Marimo moss balls are always a good plant for anything tank, they're generally easy to take care off, java moss, Christmas moss, any kind of moss that's aquatic and fairs well in low light. Find some small pieces of driftwood/lava rock to tie the java fern/moss onto.

You could try Anacharis too they can fare low light situations, hygrophilia, hornwort (not recommended), water wisteria, water sprite (if left to float). Some of these plants do need some sort of fertilizers, I would say to do more research before buying them.

You could try some easy floaters like water lettuce or duckweed, just make sure that they don't take over your tank.

The ambulia, elodea, lacefern and java fern all grow fast and a lot (then again, so does my anubias). However, I don't keep it. I let it grow over the top, then trim it back and give the offcuts to my LFS in return for some hefty discounts. :D